Water Repellent Elastic Yarn

ABSTRACT

A water repellent elastic yarn which is spinned from a polyurethane polymer and is adhered with a water repellent agent to obtain a water repellent elastic yarn, adapted for making a stretchable apparel, sportswear or underwear having better stretch characteristics and water repellency, whereby upon wicking of a wearer&#39;s sweat through apertures among neighboring elastic yarns of a fabric, the sweat will be well diffused and released outwardly to keep the wearer comfortable, while keeping the apparel easily dry after being wetted such as by rain water.

BACKGROUND OF THE INVENTION

In order to render both moisture permeability and water-proofness for a fabric, a prior art of U.S. Pat. No. 4,535,008 disclosed a moisture-permeable waterproof coated fabric by coating a microporous polyurethane layer on a basic fabric.

However, such a prior art has the following drawbacks:

-   1. Even the microporous polyurethane layer as coated on the base     fabric may make the fabric water proof, the micro pores existing in     the polyurethane layer may still entrap the moisture as emitted from     the wearer's skin to retard its outgoing release from the coated     fabric, thereby minimizing the sweat-expelling effect of the fabric. -   2. A wet coagulation process is required for coating such a     microporous polyurethane layer. For instance, complex steps     including preparation of coating solution containing PU elastomer,     repellent agent, diisocyanate adduct, nonionic surfactant, and     solvent; immersion of the coated fabric in an aqueous solution for     gelation; and drying. Such complex process steps may increase the     production cost.

Many recent functional apparels are made of elastic yarns for stretchable wearing. However, the elastic yarns have poor water repellent property. Therefore, it is expected to invent an elastic yarn which is water repellent for making fabric elastic, stretchable and water repellent.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a water repellent elastic yarn which is spinned from a polyurethane polymer and is adhered with a water repellent agent to obtain a water repellent elastic yarn, adapted for making a stretchable apparel, sportswear or underwear having better stretch characteristics and water repellency, whereby upon wicking of a wearer's sweat through apertures among neighboring elastic yarns of a fabric, the sweat will be well diffused and released outwardly to keep the wearer comfortable, while keeping the apparel easily dry after being wetted such as by rain water.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow sheet showing a process for making the water repellent elastic yarn of the present invention.

FIG. 2 is an illustration showing a fabric layer of the water repellent elastic yarns of the present invention for diffusing moisture or sweat outwardly from a wearer's skin.

DETAILED DESCRIPTION

As shown in FIG. 1, the present invention comprise a process including a plurality of steps for making a water repellent elastic yarn, and including process equipments for making the water repellent elastic yarn.

The process equipments for making the water repellent elastic yarn includes: a spinning apparatus 1, a kiss roll means 2, a heating means 3, an oil roll means 4, and a yarn-transporting means 5 for guiding, pulling and winding up the multifilament yarn as adhered with a water repellent agent 20.

The process steps for making the water repellent elastic yarn includes:

-   A. Spinning multiple filaments F from a spinning solution 11 of     polyurethane polymer and coalescing the multiple filaments F to be a     multifilament yarn Y; -   B. Adhering the multifilament yarn Y with a water repellent agent 20     to form a “wet” water repellent multifilament yarn Y1; -   C. Heating the wet water repellent multifilament yarn Y1 for     removing the solvent in the wet water repellent multifilament yarn     Y1 for drying the multifilament yarn Y1 and for bonding the water     repellent agent 20 with the multifilament yarn Y1 to be a “dry”     multifilament yarn Y2; -   D. Applying an anti-sticky oil on the dry multifilament yarn or     dried water repellent elastic yarn Y2 to be an anti-sticky water     repellent elastic yarn Y3; and -   E. Winding up the anti-sticky water repellent elastic yarn Y3 to     obtain the water repellent elastic yarn product.

As shown in FIG. 1, the spinning apparatus 1 comprises: a spinning cell 10 having a plurality of spinnerets 12 provided within the spinning cell 10 for extruding a spinning solution 11 of polyurethane polymer mixed with solvent of dimethylacetamide (DMAc) downwardly outwardly (at 80° C.) through the spinneret 12; a heated nitrogen gas (heated to be at 230° C. by a heater 130) supplied into the spinning cell 10 through a feed pipe 131 for drying the polyurethane multiple filaments F as extruded from the spinneret 12 for removing the solvent (DMAc) from the filaments F; a separator 14 connected to a lower (or bottom) portion of the spinning cell 10 for recycling the nitrogen gas and solvent (DMAc) and separating the nitrogen gas (90° C.), which is recycled through recycled pipe 142, from the solvent (DMAc) which is collected in reservoir 15 through drain pipe 143 for re-use; a nitrogen gas 13 provided for cooling in the separator 14, and is also fed into the cell 10; an air twist nozzle 16 provided under the spinning cell 10 for coalescing the multiple filaments F into a multifilament yarn Y by a compressed air stream ejecting into the air twist nozzle 16; and a ceramic guide 17 positioned at a downstream of the multifilament yarn Y for guiding the yarn Y to be transported by the yarn-transporting means 5, namely, the first roll 51 of the yarn-transporting means 5 for further processing.

The above-mentioned separator 14 may also serve as a heat exchanger for heat recovery during the spinning process, such as for preheating the nitrogen gas 13 to be fed into the spinning cell 10. The heat exchange operation is a conventional art and is not described in detail herewith.

The kiss roll means 2 includes: a kiss roll 21 rotatably mounted in an agent tray 22 filled with water repellent agent 20 in the tray 22. The kiss roll 21 has a coarse surface for absorbing the water repellent agent 20 so as to transfer the water repellent agent 20 as carried on the kiss roll 20 onto the multifilament yarn Y as led from the spinning apparatus 1 to adhere the water repellent agent 20 on the yarn Y to form a “wet” multifilament yarn Y1. The kiss roll 21 may be preferably controlled at a rotation speed, ranging from 10 rpm to 20 rpm, but not limited in this invention.

The water repellent agent 20 is essentially a water repellent agent composition containing a water repellent agent, a solvent, an emulsifier, a surfactant and any other necessary additives.

The water repellent agent 20 may be selected from: a fluorine-based water repellent agent, a silicon-based water repellent agent, and a paraffin-based water repellent agent, not limited in the present invention.

A compensation and storage tank 23 is provided adjacent to or under the kiss roll means 2, having a circulation pump 24 for pumping the water repellent agent 20 from the tank 23, through the inlet pipe 241, into the tray 22; and a discharge (or drain) pipe 221 is connected between the tray 22 and the tank 23 for recycling the agent 20 into the tank 23 for a homogeneous agitation in the tank 23. Fresh agent 20 (not shown) may also be fed into the tank 23. A filter 25 is provided between tank 23 and pump 24 for filtering off any impurities. A by-pass pipe 242 is branched from the inlet pipe 241 for pumping partial agent flow into tank 23 for adjusting the agent flow rate in pipe 241 and the agent level in tray 22 and also for helping agent agitation in tank 23.

The multifilament yarn Y, Y1 is tensioned between the first roll 51 and the second roll 52 of the yarn-transporting means 5 so that the yarn Y is tangentially contacted with the kiss roll 20 to be adhered with the water repellent agent 20. A proper kiss pressure is applied between the yarn and the kiss roll 20 to ensure a reliable penetration, spreading and adhering of the water repellent agent into “voids” or spaces among the filaments F of the yarn Y, Y1, especially as shown in a dried oil-finish yarn Y3 in FIG. 2. Therefore, the water repellent agent 20 as filled in the apertures among the filaments F of the yarn Y3 will provide a better water repellency for the yarn.

As shown in FIG. 2, when the elastic yarns Y3 are knitted or woven to be a fabric layer in contact with a wearer's skin S, his or her sweat moisture M will be wicked and diffused outwardly through the apertures among the yarns Y3. The water repellent agent 20 as adhered, bonded and filled into the “voids” among the filaments F of the yarn Y3 will preclude external water drops or rain drops from entering the wearer's skin through the fabric layer made of the water repellent agent of the present invention. Even getting wet by water or rain drops, the water repellency of the fabric as adhered with the water repellent agent in accordance with the present invention will make the fabric dry sooner for a comfortable wearing.

The “wet” multifilament yarn Y1 is then passed to the heating means 3 as guided or driven between the first roll 51 and the second roll 52, which are disposed on opposite ends of the heating means 3 for heating and drying the “wet” multifilament yarn Y1 to be a “dry” multifilament yarn Y2 as shown in FIG. 1. The yarn may be protected in a sleeve (not shown) before entering the heating means 3 to keep warm and prevent from breaking.

The heating means 3 includes a primary heater 31 having a length of 70˜100 cm, and keeping a temperature at 200˜600° C. for primarily heating and drying the wet multifilament yarn Y1 just leaving from the kiss roll 21 for removing the solvent in the water repellent agent and for bonding the water repellent agent 20 and the yarn Y1; and a secondary heater 32 having a length of 30˜60 cm and keeping a temperature at 100˜500° C., less then that at the primary heater 31 for further heating and drying the yarn Y1 to be a dry multifilament yarn Y2 after leaving the secondary heater 32. The process layout as shown in FIG. 2 is an optimum design of the present invention, but not limited.

The running speed of the yarn Y1, Y2 passing through the heating means 3 is 900 meters/minute. Therefore, the time to pass the primary and secondary heaters 31, 32 is as follows: Primary heater (31) . . . 0.047˜0.067 seconds; Secondary heater (32) . . . 0.02˜0.04 seconds.

The secondary heater 32 keeps a temperature (100˜500° C.) less than that of the primary heater 31 (200˜600° C.) because the drying temperature must be reduced in order to have a smooth oil finish at the next step, namely, by applying oil on the dry yarn Y2 by oil roll 41. The secondary heater 32 having a reduced temperature (100˜500° C.) may enhance a smooth oil finish performed at the step of “Applying anti-sticky oil on the dry yarn Y2” by the oil roll 41, which will be described hereinafter.

The dry multifilament yarn Y2 after leaving the secondary heater 32 will be applied with anti-sticky oil 40 by the oil roll means 4 as guided or driven between the first roll 51 and the second roll 52 of the yarn-transporting means 5.

The oil roll means 4 includes: an oil roll 41 rotatably mounted in an oil tray 42, having an anti-sticky oil or finish oil 40 stored in the oil tray 42, whereby upon rotation of the oil roll 41, the oil 40 will be transferred from the oil roll 41 and applied onto the dry multifilament yarn Y2 to form a dry oil-finish multifilament yarn Y3. An oil tank 43 is provided under the oil tray 42 through recycled pipe 421. A pump 44 is provided between tank 43 and tray 42 for pumping oil into tray 42 by feed pipe 441. A by-pass pipe 442 is branched from feed pipe 441 for pumping oil into tank 43 for adjusting the oil flow rate through pipe 441 and the oil level in tray 42 and also for oil agitation in tank 43. An oil filter 45 is provided between tank 43 and pump 44 for filtering off impurities.

The finish oil 40 may be a silicon-based polymer, but not limited in this invention, adapted to be applied on the yarn Y2 to be a anti-sticky yarn to prevent from sticky or tangling among yarns, affecting the winding or production of the finished yarns.

Thanks to the secondary heater 32 with reduced temperature. The anti-sticky oil 40 will maintain its optimum viscosity or viscoelasticity to be smoothly reliably applied on the yarn Y2.

After oil finish step as aforementioned, the dry oil-finish multifilament yarn Y3 is guided by the second roll 52 to be collected or wound up by a third roll, or the wind-up roll 53.

The yarn-transporting means 5 includes: the first roll 51, the second roll 52, and the third roll (also “wind-up roll”) 53. More or less rolls may be modified in consideration of a flexible production line or optimum layout in a factory, not limited in this invention.

The multifilament yarn of the present invention may comprise 20 Denier (D)/2 filaments (F); 30 D/3F; 40 D/4F, and 70 D/6F. So, DPF (Deniers Per Filament) may be about 10. However, the number of filaments are not limited in this invention. The elastic yarn is Spandex yarn, having an elongation of 400˜700%.

A water repellency test is conducted in accordance with the testing standard of AATCC (American Association of Textile Chemists and Colorists) for several water repellent yarn products of the present invention in comparison with the conventional yarns, not treated with water repellent agent.

The test results are shown in the following table (40 D/4F yarns are used for tests).

Conventional Yarns (without water Water Repellent Yarn repellent agent) (this invention) Operation Condition Grade 3 Grade 6 Remark A Grade 3 Grade 7 Remark B Grade 3 Grade 8 Remark C Remark A: Primary heater, Temperature (T ° C.): 300 Secondary heater, Temperature (T ° C.): 100 Rotation speed of kiss roll (rmp): 10 Remark B: Primary heater (T ° C.): 350 Secondary heater (T ° C.): 150 Rotation speed of kiss roll (rpm): 15 Remark C: Primary heater (T ° C.): 400 Secondary heater (T ° C.): 200 Rotation speed of kiss roll (rpm): 20

For the above table, it clearly indicates that the water repellent yarns as made in accordance with the present invention has a better water repellency (higher water repellency grade) than that of the conventional yarns, without treated with water repellent agent.

The present invention provides a water repellent elastic yarn having improved water repellency. So, the multifilament yarns of this invention may be provided for making a stretchable apparel, sportswear, underwear or clothing having nice elasticity or stretchability and having better water repellency, too.

For instance, if the wear repellent elastic yarns of this invention is provided for making a fabric in contact with a wearer's skin, the sweat moisture of the wearer will be wicked through the apertures among neighboring yarns to quickly diffuse and remove the sweat outwardly to keep a comfortable wearing. When the fabric is “impacted” by rain droplets, the water repellency of the fabric made of the water repellent elastic yarns of this invention will therefore serve as a better water repellent or water proof fabric or apparel.

The present invention may be further modified without departing from the spirit and scope of the present invention.

The elastic yarn may also include a black elastic yarn which is made by adding a desired amount of carbon black into the spinning solution, whereby upon spinning, a black elastic yarn may be obtained as dope dyed or solution dyed without further being dyed with a black dyestuff for saving energy, water and production cost. 

I claim:
 1. A process for making a water repellent elastic yarn comprising the process steps as follows: A. Spinning multiple filaments from a spinning solution of a polyurethane polymer and coalescing the multiple filaments to be a multifilament yarn; B. Adhering the multifilament yarn with a water repellent agent to form a wet water repellent multifilament yarn; C. Heating the wet water repellent multifilament yarn for removing the solvent in the wet water repellent multifilament yarn for drying the multifilament yarn and for bonding the water repellent agent with the multifilament yarn to be a dry multifilament yarn; D. Applying an anti-sticky oil on the dry multifilament yarn to be an anti-sticky water repellent elastic yarn; and E. Winding up the anti-sticky water repellent elastic yarn to obtain a water repellent elastic yarn product.
 2. A process according to claim 1, wherein said process for making the water repellent elastic yarn comprises implementation of process equipments, which comprises: a spinning apparatus for spinning said multifilament yarn, a kiss roll means for adhering said water repellent agent on said yarn, a heating means for heating and drying said yarn adhered with said water repellent agent, an oil roll means for applying anti-sticky oil on said yarn as dried, and a yarn-transporting means for guiding, pulling and winding up the yarn as adhered with said water repellent agent and finished with said anti-sticky oil thereon.
 3. A process according to claim 2, wherein said kiss roll means includes: a kiss roll rotatably mounted in an agent trough filled with water repellent agent in the tray; said kiss roll having a coarse surface for absorbing the water repellent agent so as to transfer the water repellent agent as carried on the kiss roll onto the multifilament yarn to adhere the water repellent agent on the yarn to form a wet multifilament yarn.
 4. A process according to claim 3, wherein said kiss roll is controlled at a rotation speed, ranging from 10 rpm to 20 rpm.
 5. A process according to claim 1, wherein said water repellent agent includes a water repellent agent composition containing said water repellent agent, a solvent, an emulsifier and a surfactant.
 6. A process according to claim 2, wherein said water repellent agent is selected from: a fluorine-based water repellent agent, a silicon-based water repellent agent, and a paraffin-based water repellent agent.
 7. A process according to claim 2, wherein said heating means comprises a primary heater having a heating temperature of 200˜600° C. for primarily heating and drying the multifilament yarn as adhered with said water repellent agent; and a secondary heater following said primary heater and having a heating temperature of 100˜500° C. for secondarily heating and drying said multifilament yarn.
 8. A process according to claim 2, wherein said oil roll means includes an oil roll rotatably mounted in an oil tray and an anti-sticky oil stored in said oil tray, whereby upon rotation of said oil roll, said anti-sticky oil will be applied onto the multifilament yarn as dried in said heating means.
 9. A process according to claim 2, wherein said yarn-transporting means comprises: a first roll for taking up said multifilament yarn as spinned from said spinning apparatus, and a second roll positioned after said heating means and said oil roll means for tangentially tensioning or pulling said multifilament yarn between said first roll and said second roll for adhering said water repellent agent onto said yarn before said heating means and for applying anti-sticky oil on said yarn after said heating means.
 10. A water repellent elastic yarn as made by a process comprising the following process steps: A. Spinning multiple filaments from a spinning solution of a polyurethane polymer and coalescing the multiple filaments to be a multifilament yarn; B. Adhering the multifilament yarn with a water repellent agent to form a wet water repellent multifilament yarn; C. Heating the wet water repellent multifilament yarn for removing the solvent in the wet water repellent multifilament yarn for drying the multifilament yarn and for bonding the water repellent agent with the multifilament yarn to be a dry multifilament yarn; D. Applying an anti-sticky oil on the dry multifilament yarn to be an anti-sticky water repellent elastic yarn; and E. Winding up the anti-sticky water repellent elastic yarn to obtain a water repellent elastic yarn product.
 11. An elastic yarn according to claim 10, wherein said elastic yarn is a Spandex yarn.
 12. An elastic yarn according to claim 10, wherein said elastic yarn is a black elastic yarn by adding carbon black into said spinning solution. 